1. Field of the Invention
This invention relates to an ocular antihypertensive composition for topical use which contains an effective amount of a compound of the formula ##STR2## or a salt thereof.
2. Description of the Prior Art
Heretofore various drugs have been used for the purpose of inhibiting intraocular pressure increase or lowering increased intraocular pressure. Thus, epinephrine, for instance, is known as an ocular antihypertensive agent. When epinephrine is used in patients with narrow-angle glaucoma, however, it intensifies angle closure because of its mydriatic activity and may possibly cause acute intraocular pressure rise and, furthermore, blood pressure increase and/or conjunctival pigmentation is often observed.
Parasympathomimetic drugs such as pilocarpine induce visual field deterioration or abnormal accomodation, among others.
Beta-blockers such as timolol, which are recently in wide use in the treatment of glaucoma, are reported to produce adverse systemic effects, inducing bradycardia, heart failure, asthmatic attack, etc. Therefore, beta-blockers cannot be used in patients with such symptoms.
On the other hand, beta-stimulators are expected to be usable also in such patients. However, salbutamol, which is a conventional beta-stimulator, can produce a satisfactory effect only when it is used in high concentrations in which it might cause marked conjunctival hyperemia. Therefore, salbutamol is said to be unsuited for prolonged administration.
As mentioned hereinabove, a drug which would be effective in low concentrations in the prevention or treatment of increased intraocular pressure, typically in glaucoma, with the slightest adverse effects has not been available as yet. Accordingly, the present inventors attempted a search for an agent which would be safe and have satisfactory intraocular pressure-lowering activity.
The present inventors conducted an intensive research to develop a compound which would be effective at low concentration and be free of the above-mentioned disadvantages, and have ultimately accomplished the present invention.